ACLS Drugs – Morphine

Indication of Morphine in ACLS

Morphine is indicated in ACLS for acute coronary syndrome where nitrates were ineffective in relieving the pain. Let’s say you gave your patient and nitroglycerin and it didn’t work. The patient still has chest pain. You tried another nitroglycerin and it still didn’t work. Morphine is now indicated.

Related Video – Acute Coronary Syndrome – Chest Pain Suggestive of ACS

Morphine is indicated in ACLS for acute coronary syndrome where nitrates are ineffective.

What does morphine do to the patient? When someone is having an acute coronary event (heart attack), they are scared. They think they’re going to die. And because of this, their body is releasing catecholamines, such as adrenaline and norepinephrine. These catecholamines make the heart work faster and harder and it’s going to use more oxygen.

Therefore, we’re going to give a narcotic — an opioid that is morphine. Morphine is going to relax the patient and inhibit the release of catecholamines, thus throttling back on the heart. That helps the heart work less and preserves cardiac tissue.

Read: ACLS Drugs – Lidocaine

The other benefit of morphine is that it is a vasodilator, predominantly on the venous side. Morphine is going to reduce preload to the heart and reduce the amount of blood coming back to the heart. This can actually help improve coronary perfusion by taking some of that pressure off the inside chambers of the ventricles, allowing that blood to get through the tissue and into the heart.

Morphine is also a vasodilator.

When to Avoid Morphine

Don’t administer morphine if the patient is hypotensive. Always monitor their blood pressure.

You may have an instance where your patient may be a little volume depleted. Maybe they haven’t been feeling well. Maybe their oral intake was low. The body would compensate by causing vasoconstriction to increase their blood pressure. If morphine is given in the presence of volume depletion, the patient’s blood pressure can tank. When that happens, the treatment is fluids. You can administer 200–500 mL of 0.9% normal saline to raise their blood pressure.

Any time you’re administering fluids to a cardiac patient, pay careful attention to their lung sounds. Be sure to listen to their lungs. You do not want your patient to develop pulmonary edema.

Related Video – What are Intravenous (IV) Fluids?

Dosing

What is the dosing for morphine? How much morphine do you give during a STEMI? The dosing ranges from 1–4 mg, repeated every 5–10 minutes. What you’re going to watch for is the change in their pain and the change in their blood pressure. That’s what you’re documenting every time you administer morphine. What was their pain on a 1 to 10 scale? And what was their blood pressure? A few minutes later, reassess if the morphine was beneficial.

The dosing of morphine for acute coronary syndrome.

Reversal

What if you give too much morphine and drop the blood pressure too low? Can you reverse it? Of course. If you do, give the patient Narcan (naloxone), which is dosed at 0.4 mg. In my clinical experience, it is not common to see morphine overdose for acute coronary syndrome because the dosage of morphine for acute coronary syndrome is generally on the lower end.